Description:
------------
preg_split() does not respect the limit parameter when \K is used to produce a zero-width fullstring delimiter. https://3v4l.org/kQHQZ This bug seems to be present since PHP7.3.  Other preg_split() calls using zero-width-match-producing regular expressions do not suffer the same bug. 
https://3v4l.org/3KP1T

Test script:
---------------
var_export(preg_split('~.{3}\K~', 'abcdefghijklm', 3));

Expected result:
----------------
array (
  0 => 'abc',
  1 => 'def',
  2 => 'ghijklm',
)

Actual result:
--------------
array (
  0 => 'abc',
  1 => 'def',
  2 => 'ghi',
  3 => 'jkl',
  4 => 'm',
)